The tussle between the different flavours of Brexit is expressed is ever more complex terminology.
Photograph: Justin Tallis/AFP/Getty Images

As if leaving were not bewildering enough, discussion of the various templates for Britain’s future relationship with the EU has taken on the appearance of a maths equation of late.

Brexit secretary Davis Davis says Britain should be aiming for the ambitiously named “Canada plus plus plus” model. Labour MPs who favour a softer strain of Brexit would prefer to see an alternative nicknamed “Norway minus”.

Meanwhile over in Brussels, the EU’s chief negotiator, Michel Barnier, insists Brexit remains a zero-sum game where a single plus after Canada is the best that can be hoped for. His deputy, Sabine Weyand, calls this “Canada Dry”.

So what does the blizzard of symbols add up to and how does it fit in with Theresa May’s equally baffling metaphor that we should ditch talk of hard and soft Brexit and opt for a “red, white and blue” or “bespoke” Brexit instead?

The simplest way of thinking about all these options is as a continuum, with high access to the single market and low political freedom at one end and higher levels of political autonomy combined with lower access to the single market at the other.

In this model, Norway is the best example of a country that is outside the EU, but only just. As a member of the European Free Trade Association (Efta) it achieves most of the economic benefits of single market membership, yet is required to adopt most of the EU rules as a result. This includes a requirement to allow freedom of movement, which is why those who favour its adoption by Britain like to speculate whether it can be watered down to Norway minus.

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Brexiteers prefer to come from the other direction. They take the EU’s recent free trade agreement with Canada, known as Ceta, as a starting point. It focuses on reducing tariffs for physical goods rather than dealing with the non-tariff barriers that matter to Britain’s services sector. But since UK regulations are already entirely aligned with the EU, optimists argue that it ought to be possible to add services and much else besides to reach Canada plus plus plus. With enough goodwill it could be far more than a basic free trade agreement and look like May’s specially crafted bunting.

The catch is that Brussels is unwilling to add more than basic deals for aviation and fishing to Ceta. In their eyes this remains a binary choice, no matter how many qualifiers are added.